Brake



Jan. 6, 1942; J. s. lRvlNG BRAKE n Filed June l5, 1939 I5 She'ets-Sheet l INVEN TOR.

MMRNEY.

- Jam 6, 1942- YJ. s. lRvlNG l v 2,269,268

. BRAKE Filed June 15, 1959 3 sheets-shew 2 Inn" ` INVENTOR.

3 Sheets-.Sheet Z Jan. 6, 1942. .l. s. IRVING l BRAKE Fileduune 1'5, 19519 A ORNEY.

Patented Jan. 6, 1942 BRAKE John Samuel Irving, Birmingham, England, as-

signor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application June 15, 1939, Serial No. 279,266 In Great Britain September 5, 1938 This invention relates to brakes, and is illustrated as embodied in an internal expanding brake for an automobile.

An object of the invention is to provide an improved anchorage of the brake, through a trunnion at one end of the brake shoe which permits some angular movement of the shoe and which has a iiat side (e. g. in a plane extending radially of the-brake) giving surface-to-surface anchoring engagement. This arrangement permits the shoe toshift slightly radially at its anchored end, to adjust its position to the drum, and gives relatively large anchoring surfaces.

This arrangement is especially advantageous in a brake having two leading shoes, i. e. a brake in which both shoes can shift lengthwise when applied, to anchor at either end, so that both shoes are fully eiective in the same manner as the leading shoe of an ordinary brake. A number of features of novelty relate to the adaptation of such a brake to the new anchorage, and to an improvement in the applying means of such a brake.

The above and other objects and features of the invention will be apparent from the following description of the illustrative embodiments shown in the accompanying drawings, in which:

Figure 1 is a vertical section through one improved brake emobdying my invention, in a plane just inside the head of the brake. drum, and showing the-'brake shoes in side elevation;

Figures 2, 3 and 4 are partial sections through the brake on the lines 2--2, 3,-3, and 4-4 of Figure 1 respectively;

Figure 5 is an exploded view of certain parts adjacent the end of one shoe, and including part of the applying means;

Figure 6 is a section corresponding to Figure l but showing a second modicat-ion; and

Figures '7, 8 and 9 are partial sections on the lines 1--1, 8 8, and 9 9 of Figure 6 respectively.

g The drawings illustrate the invention as embodied in brakes of the type having two leading shoes; this type of brake is covered by my United States applicationl No. 189,044, led February 7, 1938, corresponding to British Patent No. 499,598, accepted January 24, 1939. The United States application has now become Patent No. 2,168,348.

'Ihe embodiment illustrated in Figures 1-5 includes a rotatable drum I0, at the open side of which is a support such as a backing plate I2. The friction means of this brake comprises t'wo shoes I4 and I6, T-shaped in section (i. e. each having a single central reinforcing web), faced with the usual brake lining I8. The shoes are connected by return springs 20 tensioned between them.

Between the upper en ds of the shoes, the backing plate carries bolted thereto Aan anchorage comprising a bracket 22 having a circumferential bore in which are iixedly mounted anchorage bushings or sleeve members 24, of the form best shown in Figure 5. The outer ends of these members have vertical integral at extensions 26 arranged diametrically thereof, and'which are formed with curved jaws dening spaces 28 adapted to receive trunnions 3l).l The trunnions 30 have flat sides which extend radiallyA of the brake and which slidably engage the ends of the shoe webs.

The sleevemembrs 24 of the anchorage receive brake-applying plungers 32, the outer ends of which are slotted to embrace the' extensions 28,- the trunnions 30, and the ends of the shoe webs; the slots in each of the plungers 32 is deep enough so that at no time does the bottom of the slot engage the extension 28 to limit the movement of the plunger. The inner ends of the plungers 32 are beveled to form wedges engaged by rollers 34, which are in engagement with each other so they can float laterally and `which are arranged in a slot through an operating plunger lso 36 formed at one end as a hydraulic ranged in a Wheel cylinder 38.

'I'he outer ends of the plungers 32 operatively engage applying linkagesr mounted on the shoes and shown as including pairs of bellcrank levers 40 pivoted on opposite sides of the upper ends of the shoe webs. Similar pairs of bellcrank levers 42 are pivoted on the lower ends of the piston arshoe webs, and are respectively connected to the corresponding upper levers 40 by thrust meanssuch as oating links or struts 44.

The bellcrank levers 42 engage and react against adjustable anchorage plungers 46 which are slotted to embrace the lower ends of the shoe webs and which have transverse bores for trunnions 48 grooved to form flat radial surfaces engaged by the lower ends of the shoe webs. The plungers 46 are `arranged in bores in an anchor bracket 50 bolted to the backing plate, and are beveled to form wedges seating against the conical end of an adjusting member 52 having a threaded stem 54 extending through the bracket 50 to the exterior of the brake. The outer end of the stem 54 is formed for engagement by a wrench or the like, to force the adjustment member 52 inwardly .to wedge the plungers 46 apart to take up for wear of the lining l0. Member 52 is shown as radially grooved, for locking engagement with the ends of the plungers 46 after each adjustment.

In operation, depression of the brakepedal (not shown) operates the usual master cylinder ends of both shoes against thedrum.

However, the friction of the drum causes both shoes to anchor, either on the trunnlons 30 or the trunnions 48, at the ends toward which the drum isl turning, th'ereby rendering both shoes as A effective as the leading shoe of an ordinary brake. The trunnion anchorages facilitate the slight angular shoe movements necessary, and permit theV anchored end of each shoe to shift radially sufciently to adjust itself automatically to the drum.

In the embodiment of Figures 6-9 parts corresponding to parts of the first embodiment are indicated by the same reference numerals increasedv by 100.

In this embodiment, the shoes ||4 and H6 have spaced reinforcing webs, and the bellcrank levers |40 and |42 connected by the struts |44 arev arranged between the two webs ofthe corresponding shoes. 'I'he anchor bracket |22 at the upper ends of the shoes has, at opposite sides, radially arranged wear plates |23 engaged by the at sides of trunnlons |30 mounted in the ends of the shoe webs.

The wedge surfaces on plungers |32 are sloped in the opposite direction from those of plungers 32, and the operating plunger |36 (carrying the transversely-floating inter-engaging rollers |34) is arranged to be actuated by a tension element such as a rod |33 operable either by pressure in a wheel cylinder |30 or by the cable |35 of a Bowden-type mechanical control.

At the lower ends oi the shoes, the webs are formed -with rounded sockets which engage against generaily-cylindrical heads on the outer ends of plungers |45 threaded into adjusting sleeves |52 mounted in the anchor bracket |50, and the levers |42 'react against the central ilattened portions of these heads. The sleeves |52 are formed with gear teeth |53 meshing with a crown gear integrally formed on the end of the adjusting member |54, so that turning the latter will turn both sleeves simultaneously. The adjustment is locked by a spring Washer |55 yieldingly urging one of an annular series .of depressions in the base of the crown gear to seat over a locking ball |51.

The operation of this embodiment is the same as that of the first embodiment.

While two illustrative embodiments have b'een described in detail, it is not my intention to limit the scope of the invention to those particular embodiments, or otherwise than by the .terms of theappended claims.

I claim:

1. A device for use in a brake or the like to transmit thrust between a shoe having a web member and an adjacent stationary member, comprising a plunger movably mounted for lengthwise adjustment or movement in said stationary member and having its end slotted and embracing the end of said web member, and a trunnion mounted in the slotted end of said plunger and having angularly-adjustable engagement with the end of one of said members and formed with a at face engaging the end of the other of said members.

2. A device for use in a brake or the like to transmit thrust between a shoe having a web member and an adjacent stationary member, comprising a plunger movably mounted for lengthwise adjustment or movement in said stationary member and having its end slotted and embracing the end of said web member, and a trunnion mounted in the slotted end of said plunger and formed with a flat face engaging the end of one of said members.

3. A brake comprising a shoe having aweb member, a stationary member adjacent one end of the shoe, a trunnion seated in one of said members and formed with a flat face engaged by the other of said members, and applying.

means acting on the end of the shoe and including a slotted plunger embracing said trunnion and the end of said web member.

4. A brake comprising a shoe having a web member, a stationary member adjacent one end of the shoe, a trunnion seated in one of-said members and formed with a flatV face engaged by the other of said members, and applying means acting 'on the end of the shoe and including a plunger formed to clear said trunnion and a linkage mounted on the shoe and actuated by said plunger.

5. A brake having a pair of shoes having anchorages at opposite ends and applying means including linkages mounted on the shoes and permitting the shoes to shift lengthwise when applied to anchor at either end, the anchorages having associated therewith Hat-sided trunnlons giving surface-to-surface anchoring engagement and at the same time permitting some angular movement of the shoes with respect to the anchorages.

6. A brake having a shoe having anchorages at its opposite ends and having applying means` including a linkage mounted on the shoe and permitting the shoe to shift lengthwise when applied to anchor at either end, the anchorages having associated therewith flat-sided trunnlons giving surface-to-surface anchoring engagement and at the same time permitting some angular movement of the shoe with respect to the anchorages, the trunnlons having substantially flat sides engaging the endsof the shoes and curved sides fitting in corresponding grooves in the anl chorages.

7. A brake comprising a shoe having spaced web members at least at its ends, bellcrank levers mounted on the ends of the shoe between said web members, thrust means connecting said levers and balancing the thrust on one lever against the reaction of the other, an applying device acting on one lever, an anchorage member adjacent*I the applying device, a second anchorage member engaged by the other of said levers, and trunnlons through which the web members anchor on the anchorage members and which have flat sides giving surface-to-surface anchoring engagement radially of the brake.

8. A brake comprising a shoe having spaced web members at least at its ends, bellcrank levers mounted on the ends of the shoe between said web members, thrust means connecting said 1evers and balancing the thrust on one lever against the reaction of the other, an applying device acting on one lever, an anchorage mem' ber adjacent the applying device, and a second anchorage member engaged b y the other of said levers, said shoe being shiitable lengthwise when applied to anchor at either end on one of the applied to anchor at either end, the anchorages having sockets therein and having nat-sided trunnions in the sockets giving surface-to-surface anchoring engagement andat the same time permitting some angular movement of the shoes 1o to the anchorages.

with respect to the anchorages.

n 3 10. A brake having a pair of floating shoes having socket-forming anchorages at opposite 'fends and applying means permitting the shoes to shift ylengthwise and to anchor at either end, the anchorages having associated therewith in the sockets nat-sided trunnions giving surface-l to-suri'ace anchoring engagement and at the same time permitting by turning in the sockets some angular movement of the shoes with respect JOHN SAMUEL IRVI G. 

